Abstract
Life-history parameters of three species of spider mites, Schizotetranychus schizopus (ZACHER), Schizotetranychus leguminosus EHARA and Schizotetranychus cercidiphylli EHARA, were investigated under laboratory conditions (25±1°C, 50-60% RH and 15L-9D). The total developmental tiem was shorter in S. schizopus than in other two species. The intrinsic rate of natural increase (r), the net reproductive rate (RX0) and the mean generation time (T) were determined as follows : S. schizopus : r, 0.206, RX0, 27.53 and T, 16.13; S. leguminosus : r, 0.173, RX0, 27.06 and T, 19.10; S. cercidiphylli : r, 0.160, RX0, 26.05 and T, 20.42. The relationships between the difference of life-history parameters of these three species and the different patterns of defoliation of their host plants are discussed.
